Varicella zoster virus vaccine; Varivax; Vaccine - chickenpox

VACCINE INFORMATION

Chickenpox is a caused by the varicella-zoster virus (VZV). It is very common and highly contagious, occurring more often in the winter and spring. Generally, the infection is mild and not life-threatening, but there are thousands of cases each year in which people become seriously ill, requiring hospitalization, and some people do die from it.

A version of the chickenpox vaccine vaccine has been developed to prevent shingles (herpes zoster) in adults. Shingles is caused by the virus that causes chickenpox. This article focuses on the vaccine to prevent chickenpox, not shingles.

IMMUNIZATION SCHEDULE

The American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC) recommend that children receive two doses of the traditional chickenpox vaccine. The first should be given when the child is 12 - 15 months old. Children should receive the second dose when they are 4 – 6 years old.

People 13 and older who have not received the vaccine and have not had chickenpox should get 2 doses 4 to 8 weeks apart.

STATE REQUIREMENTS

In a growing number of states, the chickenpox vaccine is required before a child enters school entry.

The following are generally considered acceptable proof of immunity:

• A history of having chickenpox
• Showing that you have had the vaccine
• Showing a blood test result that indicates immunity to chickenpox

BENEFITS

The vaccine is highly effective for the prevention of chickenpox. However, a small number of people will still get chickenpox, despite having received the vaccine. Such cases are generally milder than those seen in persons who did not receive the vaccine.

RISKS

The side effects from the chickenpox vaccine are generally minor. Some of the mild possible side effects include:

• Fever
• Pain and swelling in the shot location
• A mild rash

Only in very rare instances have more moderate or severe reactions been reported, including:

• Seizures (less than 1 out of 1,000 children)
• Pneumonia (very rare)
• Anaphylaxis (a severe allergic reaction; very rare)

Other reactions, such as low blood counts and brain involvement, are so rare that their link to the vaccine is questionable.

DELAY OR DO NOT GIVE THE VACCINE

• Pregnant women should not receive the vaccine. Women who have received the vaccine should wait at least 1 month before getting pregnant.
• Children or adults who have a weakened immune system as a result of HIV/AIDS, cancer, organ transplants, or other factors should not be vaccinated for chickenpox.
• Children or adults who are allergic to the antibiotic neomycin or gelatin should not receive this vaccine.
• Children or adults taking steroids for any condition should consult with their doctor about the proper timing of chickenpox vaccine.
• Anyone who has recently received a blood transfusion or other blood product (including gamma globulin) should consult with their doctor about the proper timing of the chickenpox vaccine.
• Children receiving aspirin or other salicylates should not receive this vaccine because of the theoretical risk of Reye's syndrome.

CALL YOUR PRIMARY HEALTHCARE PROVIDER IF:

• You are not sure if the chickenpox vaccine should be given
• Any moderate to severe side effects appear after the injection
• Any symptoms occur after the vaccine that alarm you
• You have any other questions before or after receiving the vaccine

Chaves SS, Gargiullo P, Zhang JX, et al. Loss of vaccine-induced immunity to varicella over time. N Engl J Med. 2007 Mar 15;356(11):1121-9.

Centers for Disease Control and Prevention (CDC). Vaccination coverage among children entering school--United States, 2005-06 school year. MMWR Morb Mortal Wkly Rep. 2006 Oct 20;55(41):1124-6.